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排序方式: 共有5127条查询结果,搜索用时 15 毫秒
71.
张飚 《武汉理工大学学报(材料科学英文版)》2012,27(4):665-668
The surface condition, some properties and ion releasing behavior of cobalt-chromium (Co-Cr) dental alloy formed by selective laser melting (SLM) technique were investigated. Before porcelain fused firing, the surface condition of the Co-Cr alloy was observed using a scanning electron microscope (SEM), and then the density and hardness were examined. After porcelain fused firing, the interface of porcelain and alloy was observed, and then the metal-ion release of the samples was tested. SLM technique provides Co-Cr alloy higher hardness than casting method. After degassing-oxidation procedure and porcelain fused firing, the interface of the alloy and porcelain showed excellent combination. Co ion was more than Cr ion released from SLM Co-Cr alloy, the amounts of Co and Cr ions were safe according to ISO security criterion. Considering the properties before and after porcelain fused sintering process, SLM technique is suitable for dental Co-Cr alloy restoration. 相似文献
72.
Scheduling with learning effects has become a popular topic in the past decade; however, most of the research focuses on single-machine problems. In many situations, there are machines in parallel and the skills of workers might be different due to their individual experience. In this paper, we study a uniform parallel machine problem in which the objective is to jointly find an optimal assignment of operators to machines and an optimal schedule to minimize the makespan. Two heuristic algorithms are proposed and computational experiments are conducted to evaluate their performance. 相似文献
73.
John C. Femiani Chia-Yuan Chuang Anshuman Razdan 《Computer Aided Geometric Design》2012,29(2):141-149
We present a rational Bézier solution to the geometric Hermite interpolation problem. Given two points and respective unit tangent vectors, we provide an interpolant that can reproduce a circle if possible. When the tangents permit an ellipse, we produce one that deviates least from a circle. We cast the problem as a theorem and provide its proof, and a method for determining the weights of the control points of a rational curve. Our approach targets ellipses, but we also present a cubic interpolant that can find curves with inflection points and space curves when an ellipse cannot satisfy the tangent constraints. 相似文献
74.
结合实际震后现象对高原大桥的落梁破坏进行模拟分析,对震后落梁现象提出了一个新的解释,即认为地震过程中高原侧桥台后土体先发生破坏,在失去土体的支撑作用下桥台背墙在与邻梁的碰撞中被撞碎并被顶入土体中,从而引起墩台处的墩(台)梁位移增大,并最终导致落梁破坏的发生。 相似文献
75.
ZHAO Wen-hong XU Le-jun SONG Chuang WANG Zhang-quan CHEN Cheng-yuan ZHOU Hai-jun 《传感器与微系统》2012,31(5)
为解决精密球体在研磨过程中的研磨轨迹无法测量等问题,将MEMS陀螺仪测量角速度技术应用到球体研磨轨迹的测量中,研究并实现了一种基于MEMS三轴陀螺仪和STM32微控制器的轨迹测量系统.介绍了ITG3200三轴陀螺仪的特点、原理以及轨迹测量系统方案设计;分析了温度影响陀螺仪零偏的机理,基于最小二乘法原理,建立了零偏补偿模型,有效地提高零偏稳定性,满足了工程需要.进行轨迹测量系统的双自转研磨实验,结果表明:双自转研磨方式研磨均匀性较好. 相似文献
76.
阐述嵌入式系统如何实现从不同存储器上的启动方法,详细介绍了各种启动方法的实现原理、硬件配置方法、各种boot设备的操作、ROM boot和uboot映射关系表IVT的实现。 相似文献
77.
详细分析了linux系统中input输入子系统的实现代码,从input driver层、input core层、event handler层3个方面介绍了input输入子系统的实现框架及接口类型,对主要数据结构struct input dev、struct input handle、struct input handler、struct input event、input register handle和重要函数input allocate device、input register device、input register handle、input register handler以及sys文件接口实现进行详细说明。 相似文献
78.
对于很多IC设计者而言,兼容型嵌入式微处理器的设计一直以来都是一个很令人感兴趣的话题,因为可以从设计过程中学到很多宝贵的经验。兼容性设计主要有硬件兼容和软件兼容两个方面。硬件兼容包括指令集、体系架构、总线接口等。软件兼容是指使用原厂开发工具可以通过JTAG或是串口实现软件的在线调试。 相似文献
79.
80.
Fluid-structure interaction analysis of a hypothetical core disruptive accident in LMFBRs 总被引:1,自引:0,他引:1
To ensure safety, it is necessary to assess the integrity of a reactor vessel of liquid-metal fast breeder reactor (LMFBR) under HCDA. Several important problems for a fluid-structural interaction analysis of HCDA are discussed in the present paper. Various loading models of hypothetical core disruptive accident (HCDA) are compared and the polytropic processes of idea gas (PPIG) law is recommended. In order to define a limited total energy release, a “5% truncation criterion” is suggested. The relationship of initial pressure of gas bubble and the total energy release is given. To track the moving interfaces and to avoid the severe mesh distortion an arbitrary Lagrangrian–Eulerian (ALE) approach is adopted in the finite element modeling (FEM) analysis. Liquid separation and splash from a free surface are discussed. By using an elasticity solution under locally uniform pressure, two simplified analytical solutions for 3D and axi-symmetric case of the liquid impact pressure on roof slab are derived. An axi-symmetric finite elements code FRHCDA for fluid-structure interaction analysis of hypothetical core disruptive accident in LMFBR is developed. The CONT benchmark problem is calculated. The numerical results agree well with those from published papers. 相似文献